Backpack



FIG. 1 is an upper left rear perspective view of the backpack showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines showing small squares in FIG. 4 represent stitching. 

The ornamental design for a backpack, as shown and described. 